Composition for treatment of fungal diseases of plants, comprises a suspension of an active component comprising a boron chelate and/or a boron complex, in mineral oil having viscosity of 7-15 (measured according to standard NF EN ISO 3104) at 40[deg] C. An independent claim is included for a process for application of the composition on plants for the treatment of fungal diseases of plants, preferably banana and plantain cercosporiosis. ACTIVITY : Fungicide. MECHANISM OF ACTION : None given.